Punch assembly for pipe bender

ABSTRACT

A punch assembly mounted on a press having a cylinder provided with a ram reciprocally movable with respect to a pair of cooperating dies for forming bends in pipe. The punch assembly is provided with a guide movable with said ram and supporting a slide having the punch mounted thereon. A second cylinder is carried from the guide and is provided with a ram for moving the slide and punch normal to the plane of movement of the press ram to dispose said punch in a retracted position out of the plane of said pair of dies to facilitate removal of the bent pipe from the punch.

1151 3,681,965 1451 Aug. 8, 1972 [54] PUNCH ASSEMBLY FOR PIPE BENDER [72] Inventors: Erwin D. King; Aaron F. Glbson,Jr.,

both of Fayette, Ala. @5555 ASSEWELAEYElEQESFfiRS; c-.1 Csq um Ins!- Filed: April 13,1970

Appl. No.: 27,640

U.S. Cl. ..72/389, 72/427, 72/481 Int. Cl ..B2ld 7/02, B2ld 45/00 Field of Search ..72/389, 390, 427, 447, 344,

References Cited FOREIGN PATENTS OR APPLICATIONS 1,431,846 2/1966 France ..72/389 Primary Examiner-Richard J. l-lerbst Att0meyTrask, Jenkins & Hanley [57] ABSTRACT A punch assembly mounted on a press having a cylinder provided with a ram reciprocally movable with respect to a pair of cooperating dies for forming bends in pipe. The punch assembly is provided with a guide movable with said ram and supporting a slide having the punch mounted thereon. A second cylinder is carried from the guide and is provided with a ram for moving the slide and punch normal to the plane of movement of the press ram to dispose said punch in a retracted position out of the plane of said pair of dies to facilitate removal of the bent pipe from the punch.

4Claims,4Drawing1 igures PATENTEDAus 8 m2 3.681.965

INVENTORS ERWIN D. KING AARON F. GlBSON,Jr.

4' ATTORNEYS 1 PUNCH ASSEMBLY FOR PIPE BENDER BACKGROUND OF THE INVENTION Pipe bending machines are well known in the art. Such machines conventionally comprise a press provided with a hydraulic cylinder connected to a punch. A pair of pivotally mounted dies are mounted on the press below and in alignment with the punch. Thus, when a length of pipe is placed on the pair of dies and the punch moved toward said dies, the pipe will be bent around the radius of the punch.

It is frequently necessary to form deep U-shaped bends in the pipe. As a consequence thereof, the pipe frequently becomes locked or bound onto the punch during the bending operation making it difiicult to strip the bent pipe from the punch due to the close proximity of the dies. It is therefore an object of the instant invention to provide a punch assembly which will permit movement of the punch with respect to the dies so that the bent pipe can be easily stripped from the punch.

SUMMARY OF THE INVENTION In accordance with the invention, the punch assembly is mounted on a press having a cylinder provided with a vertically movable ram. The punch assembly, which is connected to the ram for movement therewith, comprises a thrust block having a pair of track-forming members mounted thereon and forming a guide for the punch assembly. A slide is supported on said track-forming members and is connected to a punch curved to conform to the desired curvature which is to be formed in the pipe. The pipe-engaging face of the punch is also curved in a transverse direction to form a semi-circle conforming to one-half of the circumferential extent of the pipe which is to be bent. A second cylinder is supported from the thrust block and is provided with a ram connected to the punch for thus moving the slide and punch in a direction normal to the path of movement of the press ram.

The pipe is supported on a pair of wing dies, each pivotally mounted on the press below the punch and having a concave curvature to support one-half of the outer surface of the pipe. Thus, the concavity of the punch and of the dies supports the pipe against crosssectional deformation during the bending operation.

A stripper arm is also mounted on the thrust block for movement therewith and extends downwardly therefrom. When the punch is moved through the plane of the pair of dies, the pipe will be bent around the radius of the punch. As the punch is drawn away from said dies, the stripper arm will move upwardly between the pair of dies to disengage the bent pipe therefrom. If the pipe is bindingly retained on the punch, as because of a sharp bend being formed therein, the second cylinder can be actuated to move the punch, with the bent pipe thereon, outwardly out of the plane of the pair of dies so that the pipe can be stripped from said punch.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a front elevation of a pipe bending press having a punch assembly embodying the invention mounted thereon;

FIG. 2 is an enlarged side elevation of the punch assembly shown in FIG. 1;

FIG. 3 is a side elevation similar to FIG. 2, but showing the punch assembly with a bent pipe bound thereon and moved into its retracted position; and

FIG. 4 is a vertical section taken on the line 4-4 of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown, our punch assembly is mountable on a press 10 for forming bends in a length of pipe 12 disposed between a punch 14 and a pair of wing dies 16 and 17. In the illustrated embodiment, the punch assembly is mounted on the bottom end of a ram 18 of a cylinder 19, said ram being actuated by the press to move downwardly and upwardly toward and away from the dies 16 and 17. The dies 16 and 17 are mounted on pivotal wings 20,.each wing having a shaft 22 fixed thereto and supported in bearings (not shown) on the press. The longitudinal configuration of each wing is such that each die assembly, or wing-die combination, has its center of gravity vertically aligned with its center of pivotal movement. Thus, the dies 16 and 17 are always disposed in a horizontal plane with their inner edges slightly spaced from each other when the ram 18 is in a raised position. The dies are free to pivot, however, when the punch 14 engages the pipe 12 and forces it in a downward direction through the plane of said dies. As shown in FIG. 2, the adjacent faces of the punch 14 and dies 16 and 17 have opposed semi-circular configurations corresponding to the circumferential curvature of the pipe 12.

As shown in FIG. 2, the ram 18 is connected through a plate 25 to a thrust block 26. A pair of laterally spaced L-shaped runners 27 are bolted to the lower face of the thrust block 26 in opposed relationship to define a track along the underside of said block whereby said block and runners form a guide for the punch assembly. A slide 30 is carried against the bottom face of the thrust block 26 by a pair of laterally projecting flanges 32 on said slide slidably carried on the runners 27. The slide 30 is connected, as by bolts 33, to the upper face of the punch 14, whereby said punch is movable with the slide 30.

As shown in FIG. 2, a plate 35 is connected, as by bolts 36, to the outer face of the thrust block 26 and projects downwardly therefrom below the plane of the runners 27. A hydraulic cylinder 38 is belted, as at 39, to the outer face of the plate 35 and is provided with a ram 42 projecting inwardly through a hole in the plate 35 and connected to the punch 14 adjacent the upper end thereof. Thus, upon actuation of the cylinder 38, its ram 42 will move the slide 30 and punch 14 along the runners 27 in a direction normal to the plane of movement of the ram 18 to move the punch 14 outwardly from the plane of the dies 16 and 17.

A stripper arm 45 is connected, as by bolts 47, to the inner face of the thrust block 26 and extends downwardly therefrom. The arm 45, which is laterally centered with respect to the dies 16 and 17, has an outwardly projecting finger 49 mounted on its lower end for movement between said dies upon upward movement of the ram 18.

In operation of the punch assembly, the cylinder 38 is actuated to cause the ram 42 to move the slide 30 and punch 14 inwardly to dispose said punch in an operative position in vertical alignment withthe dies 16 and 17. The cylinder 19 is then actuated to cause the ram 18 to force the punch assembly downwardly causing the punch 14 to bear against the pipe 12 with the thrust from the block 26 transmitted through the slide 30 to the punch 14. As the punch engages the pipe 12, the dies 16 and 17 will pivot about the shafts 22, and the pipe will be bent around the circumference of the punch 14. The cylinder 19 is then actuated to raise the punch 14 upwardly. During such upward movement, if the pipe 12 is not bound on the punch, the finger 49 on stripper arm 45 will raise the pipe from the dies 16 and 17 to facilitate its removal from the press. Should the bent pipe be bound on the punch, as shown in FIG. 4, the cylinder 38 is actuated to cause its ram 42 to slide the punch 14 and slide 30 outwardly with said slide moving along the runners 27. With the punch in such a fully retracted position, in which it is disposed in a plane outwardly from the plane of the dies 16 and 17, as shown in FIG. 3, the pipe 12 can be easily twisted off of the punch 14. With the pipe removed therefrom, the punch is moved back inwardly into vertical alignment with the dies 16 and 17 upon reactivation of the cylinder 38.

While the invention has been disclosed as being employed in combination with a press having a vertically movable punch, it is to be understood, of course, that it can be employed with a press having a horizontally movable punch such as is also conventionally employed in pipe bending presses.

We claim: j

1. in a punch assembly for a pipe bending machine having a first cylinder provided with a ram vertically movable toward and away from a pair of pivotally mounted aligned dies, said dies being disposed in a vertical plane below said ram, guide means interconnected to the ram on said first cylinder for movement therewith, said guide means being in lateral alignment with said dies and projecting horizontally outwardly from said vertically movable ram, slide means carried on said guide means for movement therewith and along said guide means, a punch mounted on said guide means extending vertically downwardly therefrom and being movable therewith, a second cylinder mounted on said guide means and having a horizontally movable ram connected to said punch for moving said slide means and punch horizontally with respect to said dies whereby said punch is movable between a retracted position in which it is disposed out of the vertical plane of said dies and an operative position in which it is in the vertical plane of said dies in alignment with said dies.

2. In a punch assembly for a pipe bending machine having a first cylinder provided with a ram vertically movable with respect to a pair of pivotally mounted aligned dies, said dies being disposed in a vertical plane below said ram, guide means interconnected to the ram on said first cylinder for movement therewith and having a track in lateral alignment with said dies and projecting horizontally outwardly from said vertically movable ram, slide means movably carried on said track and movable with said guide means, a punch mounted on said slide means for movement therewith and proje tirci g vertically downwardl tPeretgom, a second cy in er mounted at one en 0 sai guide means and having a horizontally movable ram connected to said punch for moving said slide means and punch with respect to said guidemeans and dies whereby said punch is movable to and from an operative position in alignment with said dies, an arm mounted on said guide means at its end opposite said second cylinder and projecting toward said dies, and a finger mounted on said arm at its end remote from said guide means for movement between said dies when the ram on said first cylinder is moved away from said dies to raise a pipe from said dies.

3. in a punch assembly for apipe bending machine having a first cylinder provided with a ram vertically movable toward and away from a pair of pivotally mounted aligned dies, said dies being disposed in a vertical plane below said ram, a thrust block interconnected to the ram on said first cylinder, a pair of opposed L-shaped runners. mounted on said block and forming a track therewith, said track being disposed in laterally centered relationship with respect to said dies and projecting horizontally outwardly with respect to the ram on said first cylinder, a slide carried in said track against said block and having a pair of outwardly extending flanges slidable along said runners, a punch mounted on said slide for movement therewith and projecting vertically downwardly therefrom, a second cylinder supported from said block and having a horizontally movable ram connected to said punch for moving said slide and punch along said track horizontally with respect to said dies whereby said punch is movable between a retracted position in which it is disposed out of the vertical plane of said dies and an operative position in which it is in the vertical plane of said dies in alignment with said dies.

4. In a punchassembly for a pipe bending machine havinga first cylinder provided with a ram movable toward and away from a pair of pivotally mounted aligned dies, a thrust block interconected to the ram on said first cylinder, a pair of opposed L-shaped runners mounted on said block and forming a track therewith, a slide carried in said track against said block and having a pair of outwardly extending flanges slidable along said runners, a punch mounted on said slide for movement therewith, a second cylinder supported from one end of said block and having a ram connected to said punch for moving said slide and punch along said track whereby said punch is movable to and from an operative position in alignment with said dies, arm fixedly mounted on said block at its end opposite said second cylinder, and a finger mounted on said arm at its end remote from said block for movement between said dies when the ram on said first cylinder is moved away from said dies to raise a piece from said dies. 

1. In a punch assembly for a pipe bending machine having a first cylinder provided with a ram vertically movable toward and away from a pair of pivotally mounted aligned dies, said dies being disposed in a vertical plane below said ram, guide means interconnected to the ram on said first cylinder for movement therewith, said guide means being in lateral alignment with said dies and projecting horizontally outwardly from said vertically movable ram, slide means carried on said guide means for movement therewith and along said guide means, a punch mounted on said guide means extending vertically downwardly therefrom and being movable therewith, a second cylinder mounted on said guide means and having a horizontally movable ram connected to said punch for moving said slide means and punch horizontally with respect to said dies whereby said punch is movable between a retracted position in which it is disposed out of the vertical plane of said dies and an operative position in which it is in the vertical plane of said dies in alignment with said dies.
 2. In a punch assembly for a pipe bending machine having a first cylinder provided with a ram vertically movable with respect to a pair of pivotally mounted aligned dies, said dies being disposed in a vertical plane below said ram, guide means interconnected to the ram on said first cylinder for movement therewith and having a track in lateral alignment with said dies and projecting horizontally outwardly from said vertically movable ram, slide means movably carried on said track and movable with said guide means, a punch mounted on said slide means for movement therewith and projecting vertically downwardly therefrom, a second cylinder mounted at one end of said guide means and having a horizontally movable ram connected to said punch for moving said slide means and punch with respect to said guide means and dies whereby said punch is movable to and from an operative position in alignment with said dies, an arm mounted on said guide means at its end opposite said second cylinder and projecting toward said dies, and a finger mounted on said arm at its end remote from said guide means for movement between said dies when the ram on said first cylinder is moved away from said dies to raise a pipe from said dies.
 3. In a punch assembly for a pipe bending machine having a first cylinder provided with a ram vertically movable toward and away from a pair of pivotally mounted aligned dies, said dies being disposed in a vertical plane below said ram, a thrust block interconnected to the ram on said first cylinder, a pair of opposed L-shaped runners mounted on said block and forming a track therewith, said track being disposed in laterally centered relationship with respect to said dies and projecting horizontally outwardly with respect to the ram on said first cylinder, a slide carried in said track against said block and having a pair of outwardly extending flanges slidable along said runners, a punch mounted on said slide for movement therewith and projecting vertically downwardly therefrom, a second cylinder supported from said block and having a horizontally movable ram connected to said punch for moving said slide and punch along said track horizontally with respect to said dies whereby said punch is movable between a retracted position in which it is disposed out of the vertical plane of said dies and an operative position in which it is in the vertical plane of said dies in alignment with said dies.
 4. In a punch assembly for a pipe bending machine having a first cylinder provided with a ram movable toward and away from a pair of pivotally mounted aligned dies, a thrust block interconected to the ram on said first cylinder, a pair of opposed L-shaped runners mounted on said block and forming a track therewith, a slide carried in said track against said block and having a pair of outwardly extending flanges slidable along said runners, a punch mounted on said slide for movement therewith, a second cylinder supported from one end of said block and having a ram connected to said punch for moving said slide and punch along said track whereby said punch is movable to and from an operative position in alignment with said dies, arm fixedly mounted on said block at its end opposite said second cylinder, and a finger mounted on said arm at its end remote from said block for movement between said dies when the ram on said first cylinder is moved away from said dies to raise a piece from said dies. 